That's a bold statement to make. Just because one guanosine shows tox doesn't mean all the others in current pipelines will - or that adenosine's will succumb to the same fate. It could be a class issue, or maybe not
Maybe you misunderstood my statement. VRUS was the only company clinically testing two nukes in an oral combination.
If it is, is it a purine class issue or a guanosine class issue?
Most (if not all) HCV purine analogs still in development are guanosine so I used the broader term.
There are other companies actively looking into dual-nuke with data in the foreseeable future.
I don't know of any. I'm aware of certain companies that have two nukes in their pipeline. None of which are clinically testing a dual-nuke oral combo.